A number of semiconductor devices are adversely affected by the presence of one or more of the following species: hot carriers, photons, and ionizing radiations. Such species involve breaking of existing hydrogen bonds and/or the creation of new, unsaturated silicon bonds. By ionizing radiations is meant gamma rays, such as encountered by space craft in the Van Allen belts or near Jupiter, X-rays, and ionizing ultra-violet (UV).
MOS (metal-oxide-semiconductor) devices degrade from exposure to ionizing radiation. The degradation is caused by trapping of charge in the gate oxide and by generation of interface states at the Si/SiO.sub.2 interface.
VLSI (very-large-scale-integration) devices having small channel lengths (about 1 .mu.m or less) suffer degradation from a recently identified mechanism: hot-carrier injection into the gate oxide from the channels. The hot carriers generate interface states (at the Si/SiO.sub.2 interfaces) and these can degrade transistor characteristics to the point of failure. The hot carrier problem is a present limiting factor to achieving further size reduction.
The conversion efficiency of amorphous-silicon solar cells falls significantly on exposure (of the cells) to solar radiation. Electronic traps and recombination centers (in the active region of the device) are created by the radiation.
Thus, means are required for healing the degradation in semiconductor devices caused by any of hot carriers, photons, and ionizing radiations.